WEAVING SECTIONS TS4273 Traffic Engineering. Scope of Weaving Sections Basic Indonesian Traffic Code rule give- way to the left. Two types of weaving:

WEAVING SECTIONSWEAVING SECTIONS

TS4273 Traffic EngineeringTS4273 Traffic Engineering

Scope of Weaving SectionsScope of Weaving Sections

• Basic Indonesian Traffic Code rule give-way to the left.

• Two types of weaving: single weaving sections and roundabout weaving sections

• Capacity estimate error ≤ ± 15%

• Valid for Degree of Saturation less than 0,8-0,9


Performance Measure

Weaving Section Type

Single Roundabout

Capacity Yes Yes

Degree of Saturation Yes Yes

Delay No Yes

Queue Probability No Yes

Travel Speed Yes No

Travel Time Yes No

Weaving Section Type and MeasuresWeaving Section Type and Measures

SINGLE WEAVING SECTION ROUNDABOUT WEAVING SECTION

A B

CD

A

D

C

B


VariableSingle Weaving Section

Min Avg Max

Approach Width 8 9,6 11

Weaving Width 8 11,5 20

Weaving Length 50 96 183

Width/Length 0,06 0,13 0,20

Weaving Ratio 0,32 0,74 0,95

Light Vehicle - % 49 63 81

Heavy Vehicle - % 0 3 13

Motor Cycle - % 16 32 45

Ratio Unmotorised/Motorised 0 0,02 0,06


VariableRoundabout

Min Avg Max

Approach Width 6 9 11

Weaving Width 9 12,6 20

Weaving Length 21 33,9 50

Width/Length 0,22 0,43 0,80

Weaving Ratio 0,32 0,76 0,94

Light Vehicle - % 35 60 75

Heavy Vehicle - % 0 2 3

Motor Cycle - % 20 33 55

Ratio Unmotorised/Motorised 0,01 0,05 0,18

Objectives of Weaving Sectionsof Weaving Sections

• Design and traffic control features should be selected with the aim to ensure that Degree of Saturation during the peak hour does not exceed an acceptable value (normally 0,75).

Definition of Roundabout Types Definition of Roundabout Types in MKJI 1997in MKJI 1997

Roundabout Type

Center Island

Radius (m)

No. of Entry Lanes

Entry Width

W1 (m)

Weaving Length LW (m)

Weaving Width

WW (m)

R10-11 10 1 3,5 24 7

R10-22 10 2 7,0 27 9

R14-22 14 2 7,0 32 9

R20-22 20 2 7,0 43 9

Traffic Safety ConsiderationsTraffic Safety Considerations

The traffic accident rate for four-arm roundabouts has been estimated as 0,30 accidents per million incoming vehicles as compared to 0,43 for signalised intersections and 0,60 for unsignalised intersections.

Traffic Safety ConsiderationsTraffic Safety Considerations

Roundabouts are thus much safer than other at-grade intersection types, especially at high minor flow ratios, mainly due to small conflict angles and low conflict speeds.

STEP A-1: Geometric ConditionsSTEP A-1: Geometric Conditions


A B

CD

A

D

C

B

W1

W2

WL W1

W2

W

L

STEP A-2: Traffic ConditionsSTEP A-2: Traffic Conditions

A

B

C

D

STEP A-3: Environmental ConditionsSTEP A-3: Environmental Conditions

• City Size Class Table A:3-1 p. 4-28

• Road Environment TypeTable A-3:2 p. 4-28

• Side Friction defined qualitatively by traffic engineer!

STEP B-1: Geometric STEP B-1: Geometric Weaving Section ParametersWeaving Section Parameters


A B

CD

A

D

C

B

W1

W2

WL W1

W2

W

L

STEP B-1: Geometric STEP B-1: Geometric Weaving Section ParametersWeaving Section Parameters

If:

W1 > W W1 = W

W2 > W W2 = W

221 WW

WE

STEP B-2: Base CapacitySTEP B-2: Base Capacity

WW Figure B-2:1 p. 4-32

WE/WW Figure B-2:2 p. 4-32

pW Figure B-2:3 p. 4-33

WW/LW Figure B-2:1 p. 4-33

8,15,05,13,1 13111350 WWWWEW LWpWWWC

STEP B-3: City Size Adjustment FactorSTEP B-3: City Size Adjustment Factor

City Size Inhab. (M) FCS

Very Small 0,1 0,82

Small > 0,1 - 0,5 0,88

Medium > 0,5 - 1,0 0,94

Large > 1,0 - 3,0 1,00

Very Large > 3,0 1,05

STEP B-4: Road Environment Type, Side STEP B-4: Road Environment Type, Side Friction & Unmotorised Vehicle Friction & Unmotorised Vehicle Adjustment FactorAdjustment Factor

- 0.05 0.10 0.15 0.20 0.25

COM HIGH 0.93 0.88 0.84 0.79 0.74 0.70 0.9290 (0.9257) 0.9989 0.0198 0.9107

COM MED 0.94 0.89 0.85 0.80 0.75 0.70 0.9410 (0.9543) 0.9989 0.0198 0.9220

COM LOW 0.95 0.90 0.86 0.81 0.76 0.71 0.9510 (0.9543) 0.9989 0.0198 0.9320

RES HIGH 0.96 0.91 0.86 0.82 0.77 0.72 0.9586 (0.9486) 0.9991 0.0198 0.9398

RES MED 0.97 0.92 0.87 0.82 0.77 0.73 0.9681 (0.9714) 0.9988 0.0198 0.9488

RES LOW 0.98 0.93 0.88 0.83 0.78 0.74 0.9781 (0.9714) 0.9988 0.0198 0.9588

RA HIGH 1.00 0.95 0.90 0.85 0.80 0.75 1.0000 (1.0000) 1.0000 0.0198 0.9802

RA MED 1.00 0.95 0.90 0.85 0.80 0.75 1.0000 (1.0000) 1.0000 0.0198 0.9802

RA LOW 1.00 0.95 0.90 0.85 0.80 0.75 1.0000 (1.0000) 1.0000 0.0198 0.9802

Road Environment

Type

Side Friction

Ratio of Unmotorised Vehicles a b R2 PUM FRSU

FRSU = a – b x pUM

STEP B-5: Actual CapacitySTEP B-5: Actual Capacity

FCS Table B-3:1 p. 4-34

FRSU Table B-4:1 p. 4-34

RSUCS FFCC 0

STEP C-1: Degree of SaturationSTEP C-1: Degree of Saturation

QPCU actual total flow (pcu/h)

QPCU =Qveh x FPCU

FPCU PCU factor

C actual capacity (pcu/h)

CQDS PCU

STEP C-2: Delay STEP C-2: Delay for Roundabout Weaving Sectionfor Roundabout Weaving Section

DS degree of saturation

DS 0,60

DS > 0,60

2168982,22 DSDSDT

2152525,059186,01 DSDSDT

STEP C-3: Queue Probability STEP C-3: Queue Probability for Roundabout Weaving Sectionfor Roundabout Weaving Section


32 75,10855,5565,26 DSDSDSQP

619,4967,2941,9 DSDSQP

STEP C-4: Travel Speed STEP C-4: Travel Speed for Single Weaving Sectionfor Single Weaving Section

Free-flow speed V0

pW ratio weaving flow/total flow

31430 WpV

STEP C-4: Travel Speed STEP C-4: Travel Speed for Single Weaving Sectionfor Single Weaving Section

Estimate Travel Speed V

V0 free-flow speed (kph)


5,00 115,0 DSVV

STEP C-5: Travel Time STEP C-5: Travel Time for Single Weaving Sectionfor Single Weaving Section

LW weaving section length (m)

V travel speed (kph)

VLTT W 6,3

STEP C-6: Evaluation ofSTEP C-6: Evaluation ofTraffic PerformanceTraffic Performance

• Design and traffic control features should be selected with the aim to ensure that Degree of Saturation during the peak hour does not exceed an acceptable value (normally 0,75).

Documents

WEAVING SECTIONS TS4273 Traffic Engineering. Scope of Weaving Sections Basic Indonesian Traffic Code rule give- way to the left. Two types of weaving: